Microsoft says the free upgrade offer is over, however when I upgraded
several old Dell PCs back in February/March it was still working for me.

Try this...

1. Download and run Microsoft's Media Creation Tool2.
Follow on-screen instructions to upgrade the computer to Windows 10.
Please make sure the computer is connected to the Internet throughout this
process as it must be able to validate the license3. Once in Windows 10 click the start button bottom left corner, type activation and press [Enter]. In the new window check that it shows the license as 'Windows activated with digital license'4. Assuming it activated OK get a spare 8GB or larger USB stick (WARNING: All data on this USB stick will be erased!!!) and run the Media Creation Tool again to create USB installation media5. Replace the HDD with the new SSD6.
Boot from the USB stick and install Windows 10, which should come up as
'Windows activated with digital license' after it had a chance to
validate the license via the Internet

Having
upgraded the hard drive with Windows 10 you could also use disk cloning software to copy the old drive contents to the new SSD, also you would need a USB to SATA adapter for that. Some prefer to do it this way since it retains user data/compatible applications and gives you the ability to go back to Windows 8.1 within 30 days.

Microsoft says the free upgrade offer is over, however when I upgraded …Microsoft says the free upgrade offer is over, however when I upgraded
several old Dell PCs back in February/March it was still working for me.Try this...1. Download and run Microsoft's Media Creation Tool2.
Follow on-screen instructions to upgrade the computer to Windows 10.
Please make sure the computer is connected to the Internet throughout this
process as it must be able to validate the license3. Once in Windows 10 click the start button bottom left corner, type activation and press [Enter]. In the new window check that it shows the license as 'Windows activated with digital license'4. Assuming it activated OK get a spare 8GB or larger USB stick (WARNING: All data on this USB stick will be erased!!!) and run the Media Creation Tool again to create USB installation media5. Replace the HDD with the new SSD6.
Boot from the USB stick and install Windows 10, which should come up as
'Windows activated with digital license' after it had a chance to
validate the license via the InternetHaving
upgraded the hard drive with Windows 10 you could also use disk cloning software to copy the old drive contents to the new SSD, also you would need a USB to SATA adapter for that.

Thanks, I’ll see if I can give that a go.

7th Aug

As above, but consider there is no requirement to pay / licence the installation unless you want to customise the appearance by say changing the default desktop image to that of a cute cat. Still have the helpful forced updates if licenced or not.

7th Aug

As Andyroyd said....cheapest option is no licence at all. just put up with not being able to change the wallpaper etc.....

or another naughty option.....is speak to someone/friend/relative who works in a large office and ask them to get you the serial number off one of the PC's Big companies never use the windows key that is stuck to the PC, they re-image with their own build and license using Volume licensing with a generic key, the stickered key on the PC never gets used haha